The objective is metabolic coordination and intercellular transfer of chemicals in cultivated pancreatic islets using multichannel microfluorometry to correlate with metabolic parameters and secretory triggers. Metabolites leading to blue-fluorescence associated NAD(P) reversibly yields NAD(P)H transients or fluorescent tracers are injected into a cell within a cluster of endocrine cells. Intercellular transit time (tau) of e.g. 6-carboxyfluorescein was 0.4 - 1 sec in glucose-free media, somewhat shorter (approximately 0.2 sec) in presence of 16.7 mM glucose. In glucose-free media the communication seemed selective into close or remote neighbors. In high glucose (16.7 mM) the number of cells communicating nearly doubled and generally involved those clustered around the injected cell. Injection of Ca ions suggests a prolongation of tau (approximately 1.5 - 2 sec). The largest glucose-6-P triggered transients are in islet cells maintained 17 h. in 0.005-0,25 mM glucose and transferred to glucose-free medium, but there is no clear-cut evidence of intercellular transfer. When the islet cells are maintained in 1-16.7 mM glucose for longer durations, reverse transients NAD(P)H reversibly yields NAD(P) are observed. The latter suggest enhanced activity of reoxidative pathways, e.g. extramitochondrial-mitochondrial shuttles. The current goals are: 1) correlation of tau to glucose levels, drugs stimulating insulin release (e.g.1-methyl 3-isobutylxanthine, tolbutamide) or other controlling factors; 2) definition of functional cooperation between islet cells via observation of metabolite-triggered NAD(P)H transients and their regulation by organelle activity (e.g.mitochondrial); 3) elaboration of techniques required to retrieve fluorometrically followed clusters for subsequent morphometric analysis of gap junctions. The significance of these studies lies in the possibility to develop a body of knowledge on the operation of islet cells, via an in situ approach at pace with the intra- and intercellular processes.